1. Field of the Invention
The present invention relates generally to a spindle motor and an optical disc drive employing the spindle motor, and more particularly, to a spindle motor with air-guiding holes and an optical disc drive employing the spindle motor.
2. Description of Related Art
Optical discs have gradually replaced conventional magnetic storage medium and become a type of indispensable optical storage medium for modern people due to the facts that the optical disc is inexpensive, easy to carry, large in storage size and easy for reservation, and can store data for a long time. Because of the widespread use of the optical discs, optical disc drives for reading the optical discs have also become a common and necessary electronic product.
In general, a traverse inside the optical disc drive is provided with a spindle motor for carrying an optical disc for high speed rotation and an optical pickup for reading data on the optical disc. The spindle motor usually includes a stator, a rotor, and a base plate. The base plate is mounted to the traverse and the stator is fixed to the base plate. The rotor is typically pivotably mounted with respect to the stator in a floating manner. In particular, the stator may include a bearing portion and a plurality of coil portions connected to a periphery of the bearing portion. The rotor may include a rotary shaft pivotably mounted in the bearing portion in a floating manner and an annular magnetic element disposed adjacent the coil portions. The annular magnetic element is, for example, a permanent magnet.
A user can place an optical disc on the spindle motor to rotate the optical disc. Since the optical disc is an external load from the perspective of the motor, in case of a high unbalance of the optical disc, the motor may bear a large external load thus causing an increased chance of contact and abrasion between the rotor and the stator. After a long term operation, the coil portions of the stator may generate a large amount of heat and conduct the heat to the bearing portion of the rotor thus causing deterioration of the quality of lubricating oil and degradation of the load capacity of the oil film in the bearing portion. This phenomenon may accelerate the wear between the rotor and the stator thus shortening the lifespan of the motor. In addition, with the rotating speed of the optical disc drive being increased, the spindle motor also generates more heat correspondingly, which may cause an overheat issue of the bearing portion to be more severe.